Chapters 28-32

Question 1

Irregular in shape.

Answer 1

Asymmetrical.

Question 2

Arrangement of body parts so there are distinct left and right halves that mirror each other.

Answer 2

Bilateral symmetry.

Question 3

Hollow ball of cells that gives rise to all the tissues and organs of an adult body.

Answer 3

Blastula.

Question 4

An animal’s shape, symmetry, and internal organization.

Answer 4

Body plan.

Question 5

In bilaterally symmetric animals, the development of a head end with a concentration of nerves and sensory structures.

Answer 5

Cephalization.

Question 6

In animals, the outer layer of embryonic tissue from which the skin and nervous system develop.

Answer 6

Ectoderm.

Question 7

Inner layer of embryonic tissue from which the digestive organs develop in animals.

Answer 7

Endoderm.

Question 8

An internal skeleton composed of a hard material, such as bone.

Answer 8

Endoskeleton.

Question 9

A hard external covering of some invertebrates.

Answer 9

Exoskeleton.

Question 10

Middle layer of embryonic tissue in animals from which the skeleton and muscles develop.

Answer 10

Mesoderm.

Question 11

Arrangement of body parts around a central axis.

Answer 11

Radial symmetry.

Question 12

Parasitic flatworm of the class Trematoda.

Answer 12

Fluke.

Question 13

Free-swimming, jelly-like, often umbrella-shaped body form of a cnidarian; jellyfish.

Answer 13

Medusa.

Question 14

Barbed harpoon within a cnidocyte of a cnidarian; used to spear prey.

Answer 14

Nematocyst.

Question 15

Cylindrical, pipe-shaped body form of a cnidarian, usually attached to a rock or other object.

Answer 15

Polyp.

Question 16

Describes an organism that remains attached to a surface for its entire lifetime.

Answer 16

Sessile.

Question 17

Needles of silica or calcium carbonate in the skeleton of some sponges.

Answer 17

Spicules.

Question 18

The primitive brain contained in one anterior segment of an annelid.

Answer 18

Cerebral ganglion.

Question 19

In a mollusk, muscular region used for locomotion.

Answer 19

Foot.

Question 20

Heavy fold of tissue that surrounds the visceral mass of mollusks.

Answer 20

Mantle.

Question 21

Rasping tongue-like organ of mollusks used in obtaining food.

Answer 21

Radula.

Question 22

External bristles of annelids.

Answer 22

Setae.

Question 23

Central section of a mollusk’s body that contains its organs.

Answer 23

Visceral mass.

Question 24

In arthropods, a structure that extends from the body wall.

Answer 24

Appendages.

Question 25

Role played by an individual insect in a colony.

Answer 25

Caste.

Question 26

Eye made of thousands of individual visual units.

Answer 26

Compound eye

Question 27

The body region of some arthropods that consists of a head fused with a thorax.

Answer 27

Cephalothorax.

Question 28

Paired mouthparts of arachnids and their relatives that are modified into fangs or pincers.

Answer 28

Chelicerae.

Question 29

Slender, fingerlike organ of excretion that opens into the gut of certain arthropods.

Answer 29

Malpighian tubule.

Question 30

Chewing mouthpart found in many arthropods.

Answer 30

Mandible.

Question 31

Dramatic physical change through which an immature organism passes as it grows to adulthood.

Answer 31

Metamorphosis.

Question 32

A periodic shedding of an arthropod’s exoskeleton; also found in some reptiles.

Answer 32

Molting

Question 33

In arachnids, a second pair of appendages that are modified to catch and handle prey.

Answer 33

Pedipalps.

Question 34

Modified appendages in arthropods that secrete silk.

Answer 34

Spinneret.

Question 35

Mid-body region in arthropods.

Answer 35

Thorax.

Question 36

Deuterostome with completely internal endoskeleton, notochord, pharyngeal slits, and a post anal tail.

Answer 36

Chordate.

Question 37

Chordates without a backbone; tunicates and lancelets.

Answer 37

Invertebrate chordate.

Question 38

Flexible rod of tissue along the back of a chordate that aids in locomotion.

Answer 38

Notochord.

Question 39

Water-filled system of interconnected canals and tube feet that aids echinoderms in movement.

Answer 39

Water-vascular system.